Hello!
After discussion with Stas, we want to have a regular deployment window for Wikidata Query Service. This should help give better visibility on when new version arrives and help track issues with those new versions. I will take care of the deployments (with Stas' support, of course).
The deployment window is: every Monday, from 7pm CET (10am PST - 5pm UTC) starting from Monday April 11th.
Let me know if you have any question or if you know of another place where I should publicize this deployment window.
Take care,
Guillaume